Device for measuring a torque between two coaxial shafts

Abstract

A device for measuring a torque between first and second coaxial shafts comprises a ring secured to one of the shafts and axially split so as to receive an axial key on the other shaft. The ring portions which are adjacent the key are operative to make the measurements and comprise flexible parts on which strain gauges are stuck.

What is claimed is:  
     
       1. A device for measuring a torque between first and second shafts which are arranged coaxially to each other, said device comprising: 
       an axially split ring rigidly connected to said first shaft and coaxial therewith, said axially split ring defining an axial slot which is parallel to a central longitudinal axis of said first and second shafts;  
       a radially inwardly extending key disposed along an axial length on an inside of said second shaft, said radially inwardly extending key being received in said axial slot;  
       said axially split ring having a main part and at least one tail which borders said axial slot and which is separated from said first shaft;  
       said at least one tail including an end portion having a key-contacting surface, and a connecting portion connecting said end portion to said main part of said axially split ring, said connecting portion extending in either an axial or obliquely axial direction and having a surface defined by a thickness of said axially split ring; and  
       a strain gauge carried by said thin portion on said surface defined by said thickness of said axially split ring, wherein a torque acting between said first and second shafts creates forces acting on said key-contacting surface of said at least one tail and said forces are transmitted as bending forces to said connecting portions and thereby to said strain gauge which is connected to a measuring device by electrical wiring.  
     
     
       2. The device according to claim  1 , wherein said at least one tail is two pairs of tails, each pair of said two pairs of tails pointing in opposite axial directions of said radially inwardly extending key. 
     
     
       3. The device according to claim  2 , wherein each tail of said two pairs of tails are disposed opposite one another and each pair of said two pairs of tails are disposed on opposite sides of said radially inwardly extending key. 
     
     
       4. The device according to claim  1 , further comprising a bearing provided between said axially split ring and said second shaft.